US7089673B2 - Optical angle sensor - Google Patents

Optical angle sensor Download PDF

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Publication number
US7089673B2
US7089673B2 US10/974,254 US97425404A US7089673B2 US 7089673 B2 US7089673 B2 US 7089673B2 US 97425404 A US97425404 A US 97425404A US 7089673 B2 US7089673 B2 US 7089673B2
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United States
Prior art keywords
guide
measurement
angle sensor
rotary angle
measurement member
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Expired - Fee Related
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US10/974,254
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English (en)
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US20050086815A1 (en
Inventor
Josef Siraky
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Sick Stegmann GmbH
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Sick Stegmann GmbH
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Priority claimed from DE10356328A external-priority patent/DE10356328A1/de
Application filed by Sick Stegmann GmbH filed Critical Sick Stegmann GmbH
Assigned to SICK STEGMANN GMBH reassignment SICK STEGMANN GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SIRAKY, JOSEF
Publication of US20050086815A1 publication Critical patent/US20050086815A1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
    • G01D11/02—Bearings or suspensions for moving parts
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/34707—Scales; Discs, e.g. fixation, fabrication, compensation

Definitions

  • the invention concerns an optical sensor for determining angles of rotation.
  • Such optical systems all work on the principle of the object to be measured moving in a measurement direction relative to a stationary scanning system. Measurements concerning the object are then processed as light and directed onto electrical photoreceivers.
  • One commonly used principle for operating such optical systems is the transmitted light principle, in which the object, which could be made of glass, transparent plastic, or metal with light-transparent structures etched out, is penetrated by light, preferably parallel light. On the opposite side, the light which has been modulated by the movement of the object is transformed by photoreceivers into electrical signals. This method is relatively simple and economical to carry out.
  • optically scanning the object for light reflected by it is optically scanning the object for light reflected by it.
  • the principle of interferometric scanning of the object is the principle of interferometric scanning of the object.
  • coherent light interferes on a lattice with a lattice width on the order of the wavelength of the light to produce an extinction or amplification of the light and, thus, a corresponding electrical modulation at the optical receiver. It is known to employ this technique in sensors employing either the transmitted light principle or the reflection principle.
  • Another object of the invention is to keep the distance between the rotating member and the static or stationary member and/or the optical/electrical converter very small, e.g. in the range of 10–20 ⁇ m. The spacing and the centering should then be preserved even when the members are subjected to very large axial and radial accelerations.
  • An optical rotary angle sensor constructed according to the invention has at least one member to be measured (“measurement member”) that is movable in a measurement direction and which has light-permeable and impermeable regions. There is at least one second measurement member which is static relative to the former in the measurement direction and/or at least one static photoelectric transducer. According to the invention, the measurement members are oriented relative to each other in the measurement direction by a guide provided between them. This is a simple and economical solution for centering, and the centering can be independent of the shaft bearing.
  • a structurally simple and economical guide made in accordance with this invention has at least one guide element arranged on one of the measurement members and a guide recess formed in the other measurement member, in which the guide element is guided.
  • the guide element is preferably configured as a guide pin.
  • the guide element can also be a single central guide pin which sits in a central guide recess and thereby centers the measurement members. If this central guide pin, sitting in a corresponding central guide recess on the other measurement member, has a pointed configuration, and engages the bottom of the guide recess with its point, friction losses can be minimized. This permits, without problems, rotary speeds of up to 10,000 rpm and more, as are required in present-day shaft encoders.
  • Some friction at the guides is solved or at least lessened by using a transparent fluid with adhesive action as a lubricant between the measurement members to lessen the friction when the two rotate relative to each other.
  • the viscous material has the further major advantage that it can be employed to keep the measurement members spaced apart, and the spacing can be very small depending on the quantity of the medium that is present; e.g. it can be in the range of 10–20 ⁇ m.
  • the viscous medium has the further major advantage that, as a result of the adhesive action, the non-rotatable static measurement member or transducer which is able to move in the axial direction is kept at a constant distance from the rotating measurement member as dictated by the viscous medium.
  • An absolute minimum spacing between the members is set by the guide, e.g. by the length of the guide pin and the depth of the guide recess.
  • the guide is formed by a guide groove in one of the measurement members, running in the measurement direction, and at least one pin at the other measurement member that engages the guide groove.
  • the guide groove can have a cross-section which narrows in the direction of the depth of the groove, in particular a triangular cross-section.
  • the guide groove forms a concentric guide for the guide pin or pins.
  • the measurement members are then guided somewhat similar to a record player arm, where the needle travels in the record grooves.
  • the guide element can also be configured as a guide fin.
  • the measurement members are configured so that they can be guided centrally as well as form-fitted relative to the spacing between each other. This can be accomplished with a conically extending concentric depression located in one measurement member, and a conical pin sitting on the other measurement member for engaging the depression.
  • the at least one static measurement member and/or the at least one static photoelectric transducer is non-rotatable relative to measurement members and the rotary angle being measured by a stator coupling, but remains movable in the axial and the radial directions.
  • the rotation-rigid stator coupling preferably defines a parallelogram.
  • the rotating measurement member is advantageously guided by an angularly true shaft coupling.
  • the principle of the invention can also be used with non-optical rotary angle sensors.
  • FIG. 1 is a perspective front elevational view, partially in section, of two measurement members
  • FIG. 2 is an exploded view, in cross-section, through the measurement members of FIG. 2 ;
  • FIG. 3 is a schematic top view of the first and second measurement members of another embodiment.
  • FIG. 4 is a cross-section through the measurement members of FIG. 3 , when placed on top of each other.
  • a rotary angle sensor has a first measurement member 1 that is able to move in a measurement direction and a second, static measurement member 2 . By measuring the motion of measurement member 1 relative to the measurement member 2 , a rotary angle can be determined, as has long been known.
  • the measurement members 1 and 2 lie with a certain spacing on top of each other, a bottom side 3 of the first measurement member 1 being opposite a top side 4 of the second measurement member 2 .
  • a guide between measurement members 1 and 2 maintains them concentric with respect to each other.
  • the guide consists of a guide element 10 projecting from bottom side 3 of the first measurement member 1 and a guide recess 12 provided on top side 4 of the second measurement member 2 , in which the guide element 10 is guided.
  • guide element 10 is configured as a guide fin 5 protruding from the under side of the first measurement member and guide recess 12 as a concentric guide groove 6 with a narrowing triangular cross-section in the top side of the second measurement member.
  • the guide element 10 has a shape adapted to that of the guide recess 12 as is shown in FIG. 2 .
  • a form-fitted connection then exists between the measurement members 1 and 2 in at least one direction which does not correspond to the measurement direction. In the illustrated embodiment, a form fit occurs in the radial direction. Due to guide fin 5 traveling in the guide groove 6 , the measurement members are precisely guided relative to each other during rotations with only a very small distance between them.
  • the guide element is only a single central guide pin that narrows to a point.
  • the pin engages a central, rotationally symmetrical guide recess to center the measurement member.
  • Only the tip of the central guide pin engages the bottom of the guide recess, which is preferably tapered to correspond to the shape of the pin. This provides a very exact adjustment in the radial direction and minimizes unavoidable friction losses. This permits without problems rotary speeds in the range of 10,000 rpm or more, as are required in present-day shaft encoders.
  • a viscous, preferably optically transparent, medium is placed between them to enable an optical scanning of the measurement members 1 and 2 .
  • this medium has an adhesive effect so that overall the spacing between the two measurement members 1 and 2 can be set with the medium. This distance can be very small (10–20 ⁇ m) and is limited in a downward direction by the height of the guide element 10 and the depth of the guide recess 12 , as is illustrated in FIG. 4 .
  • a fluid barrier 16 is provided, for example, at the edge of one of the measurement members. Since, however, the medium can disappear over time, a reservoir recess 18 can be provided in one or both measurement members, which is filled with viscous medium and from which the viscous medium can flow into the space between the two measurement members 1 and 2 . This is schematically shown in FIG. 4 only, but applies to the other embodiments as well.
  • guide elements 10 are formed by three guide pins 7 , which are arranged on a corresponding partial circle 8 having the same radius as the groove.
  • the guide pins 7 have a conical shape, so that they engage guide groove 6 and provide a guiding effect in the manner of the earlier described fin 5 .
  • the guide pins can be form-fitting in the radial direction or, as shown, have only their tips 14 engage and be guided by the bottom of the groove. Once again, the viscous medium occupies the spacing between the measurement members.
  • the at least one static measurement member 1 or 2 and/or the at least one static photoelectric transducer are non-rotatably mounted relative to the rotary angle being measured, yet they remain movable in both the axial and the radial directions, so that the centering of and relative spacing between the measurement members are done exclusively by the guide according to the invention to assure an orientation that is as exact as possible.
  • the non-rotational arrangement preferably defines a parallelogram, and/or the rotating measurement member should be guided by an angularly true shaft clutch. In this manner, the guidance provided by the present invention assures an optimal orientation of the measurement members of rotary angle sensors.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Length Measuring Devices By Optical Means (AREA)
US10/974,254 2003-10-27 2004-10-26 Optical angle sensor Expired - Fee Related US7089673B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE10350211 2003-10-27
DE10350211.4 2003-10-27
DE10356328A DE10356328A1 (de) 2003-10-27 2003-11-28 Optischer Weglängen- oder Drehwinkelsensor
DE10356328.8 2003-11-28

Publications (2)

Publication Number Publication Date
US20050086815A1 US20050086815A1 (en) 2005-04-28
US7089673B2 true US7089673B2 (en) 2006-08-15

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US10/974,254 Expired - Fee Related US7089673B2 (en) 2003-10-27 2004-10-26 Optical angle sensor

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US (1) US7089673B2 (de)
EP (1) EP1528369B1 (de)
JP (1) JP2005128021A (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111272122B (zh) * 2020-03-27 2021-08-31 厦门大学 一种拖拉机后桥差速器轴承座综合测量系统及测量方法

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1550185A (en) 1975-04-10 1979-08-08 Neil Holdings Ltd James Distance measuring gauge
DE3118607A1 (de) 1980-07-21 1982-03-04 Mitutoyo Mfg. Co., Ltd., Tokyo Laengenmessgeraet
US4414754A (en) * 1982-03-04 1983-11-15 The Laitram Corporation High resolution compass card position decoder
US4660036A (en) * 1985-05-17 1987-04-21 Rockwell International Corporation Amplified motion encoder
US4719449A (en) * 1985-10-01 1988-01-12 Jice Automation Transport apparatus for transporting part-carrying members to various work stations and for reading data encoded on said part-carrying member
US5129725A (en) * 1986-11-04 1992-07-14 Canon Kabushiki Kaisha Method of optically detecting position of object and position detecting apparatus using the method
DE10060574A1 (de) 2000-12-06 2002-06-13 Heidenhain Gmbh Dr Johannes Multiturn-Codedrehgeber
US6442861B1 (en) * 1999-03-19 2002-09-03 Dr. Johannes Heindenhain Gmbh Position measuring device
US20020144413A1 (en) * 2001-04-05 2002-10-10 Hoskins Steven R. Multi-bit optical sensor code wheel
US20020148123A1 (en) * 2001-03-09 2002-10-17 Johann Mitterreiter Coupling and angle encoder with such a coupling
US6615501B2 (en) * 2001-01-18 2003-09-09 Raytheon Marine Gmbh Angle detection device with a data transmission path on an n.360° bearing assembly of a gyro compass
US20030182816A1 (en) * 2002-03-30 2003-10-02 Helmut Huber Linear encoder and linear guide assembly with the linear encoder
US20040244210A1 (en) * 2003-04-11 2004-12-09 Helmut Harrer Position measuring system
US20050022396A1 (en) * 2003-07-31 2005-02-03 Alps Electric Co., Ltd. Absolute angle detecting device

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5399970A (en) * 1977-02-14 1978-08-31 Nippon Gakki Seizo Kk Rotating angle detector
DE3929629A1 (de) * 1989-09-06 1991-03-07 Zeiss Carl Fa Laengen- oder winkelmesseinrichtung
US5198740A (en) * 1989-10-04 1993-03-30 University Of Utah Research Foundation Sliding contact mechanical/electrical displacement transducer
US5569912A (en) * 1993-09-30 1996-10-29 U.S. Philips Corporation Optical velocity measuring with efficient use of radiation passing through patterns on discs
GB2294111A (en) * 1994-10-08 1996-04-17 Motorola Semiconducteurs Steering column rotation sensor
JPH1123322A (ja) * 1997-07-08 1999-01-29 Alps Electric Co Ltd 光学式エンコーダ

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1550185A (en) 1975-04-10 1979-08-08 Neil Holdings Ltd James Distance measuring gauge
DE3118607A1 (de) 1980-07-21 1982-03-04 Mitutoyo Mfg. Co., Ltd., Tokyo Laengenmessgeraet
US4414754A (en) * 1982-03-04 1983-11-15 The Laitram Corporation High resolution compass card position decoder
US4660036A (en) * 1985-05-17 1987-04-21 Rockwell International Corporation Amplified motion encoder
US4719449A (en) * 1985-10-01 1988-01-12 Jice Automation Transport apparatus for transporting part-carrying members to various work stations and for reading data encoded on said part-carrying member
US5129725A (en) * 1986-11-04 1992-07-14 Canon Kabushiki Kaisha Method of optically detecting position of object and position detecting apparatus using the method
US6442861B1 (en) * 1999-03-19 2002-09-03 Dr. Johannes Heindenhain Gmbh Position measuring device
DE10060574A1 (de) 2000-12-06 2002-06-13 Heidenhain Gmbh Dr Johannes Multiturn-Codedrehgeber
US6615501B2 (en) * 2001-01-18 2003-09-09 Raytheon Marine Gmbh Angle detection device with a data transmission path on an n.360° bearing assembly of a gyro compass
US20020148123A1 (en) * 2001-03-09 2002-10-17 Johann Mitterreiter Coupling and angle encoder with such a coupling
US20020144413A1 (en) * 2001-04-05 2002-10-10 Hoskins Steven R. Multi-bit optical sensor code wheel
US20030182816A1 (en) * 2002-03-30 2003-10-02 Helmut Huber Linear encoder and linear guide assembly with the linear encoder
US20040244210A1 (en) * 2003-04-11 2004-12-09 Helmut Harrer Position measuring system
US20050022396A1 (en) * 2003-07-31 2005-02-03 Alps Electric Co., Ltd. Absolute angle detecting device

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US20050086815A1 (en) 2005-04-28
EP1528369A1 (de) 2005-05-04
JP2005128021A (ja) 2005-05-19
EP1528369B1 (de) 2014-03-12

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